Battery powered sharpener? Never heard of it. I've been using a Spyderco Sharpmaker for a couple of months now. It is easy to use and puts a really good edge on all my knives. I keep it set up at all times for quick touch-ups. I highly recommend it. Also, get a copy of the Sharpening FAQs off rec.knives. Even if you've been sharpening knives for years you'll get a lot of good information from it.
I would recommend the Edge Pro Apex. This is a manual sharperner. I saw it recommended by a number of people on the other knife site a few months ago. I bought one and was very pleased. Check it out at:
I would stay away from any power driven gimmick sharpeners.Regardless of how good a sharpening job they do they will put scratches on the steel which isn't to cool on an expensive custom knife.If you don't care how your kitchen cutlery looks they might be okay for a fast sharpening job but I prefer a steel for touch ups.